This invention relates in general to antifriction bearings and, more particularly, to a tapered roller bearing that is capable of sustained operation in the absence of its normal supply of lubrication.
Tapered roller bearings offer many advantages which other types or combinations of bearings do not. For example, a pair of tapered roller bearings will carry extremely heavy radial and thrust loading, and the individual bearings may be adjusted against one another to control radial and axial play. Due to their large load carrying capacity in both radial and axial directions, it is often possible to replace a combination of three other bearings with only two tapered roller bearings and still achieve the desired bearing life.
Due to the tapered configuration of the rollers radial loads on the rollers create an axial force component which tends to expel the rollers from the annular space between the two races, that is, from between the cup and cone. This expulsion force is resisted by means of a thrust rib on one of the races, usually the cone. Thus, as the cup and cone rotate relative to each other the large diameter end faces of the tapered rollers experience rolling and sliding contact against the thrust rib. Unless a film of lubricant is maintained between the roller end faces and the thrust rib, the bearing will overheat and sustain damage.
In some machinery it is important to have safety features which will enable the machinery to operate even though its lubricating system is disabled. This is particularly true of helicopters.